I'll go along with Firestone too.
What's unusual about this bike is it looks like a middleweight frame that was for 26 x 1.75wheels. It might be the same frame as horsefarmer's red one, but a 26 x 1 3/8 wheel is a little taller than 26 x 1.75, I wonder if the frame is a tiny bit larger, and maybe the forks longer for the skinny wheels. Probably not, same frame. With a coaster brake one speed, they didn't have to worry about handbrakes fitting properly.
Notice it came from the factory that way, it has skinny fenders on the wider frame. That's what I've never seen and can't find when searching around the internet. They either have a diamond lightweight style frame or wider tires on a middleweight frame.
So I think that's a fairly rare bike.